If the supply voltage for an amplifier, which amplifies the audio-frequency signal for a loudspeaker arrangement, is turned on or off, the connected loudspeaker will generally produce a turn-on or turn-off click. In order to avoid this, it is known to include a contact in the signal path after the amplifier, which contact is actuated together with the contact for the supply voltage. This contact is susceptible to failure and is not actuated when the supply voltage is turned on or off respectively by removing or inserting the mains plug.
Furthermore, from DE-OS No. 23 22 317 an amplifier for acoustic signals is known, which eliminates the clicking noise upon turn-on of the power supply in that the output potential of the amplifier stage is continuously increased from a basic value to the predetermined operating voltage. This amplifier is provided with a starting switch comprising a transistor circuit, whose base-emitter junction is connected in parallel with the charging resistor of a capacitor which is connectable to the power supply voltage. This circuit arrangement is comparatively intricate and moreover it is only intended and suitable for eliminating turn-on clicks.